1999/08/27 by Francis W. Starr, Francesco Sciortino, H. Eugene Stanley · 8 citations
Earth and Planetary Sciences · Engineering · Materials Science · Physics and Astronomy · #High-pressure geophysics and materials #Material Dynamics and Properties #Phase Equilibria and Thermodynamics #cond-mat
paper · pdf · doi:10.1103/physreve.60.6757
14 pages, 15 figures
arxiv created 1999/08/27 · openalex publication_date 1999/12/01 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present molecular dynamics simulations of the extended simple-point-charge model of water to probe the dynamic properties at temperatures from 350 K down to 190 K and pressures from 2.5 GPa (25 kbar) down to -300 MPa (-3 kbar). We compare our results with those obtained experimentally, both of which show a diffusivity maximum as a function of pressure. We find that our simulation results are consistent with the predictions of the mode-coupling theory for the dynamics of weakly supercooled liquids--strongly supporting the hypothesis that the apparent divergences of dynamic properties observed experimentally may be independent of a possible thermodynamic singularity at low temperature. The dramatic change in water's dynamic and structural properties as a function of pressure allows us to confirm the predictions of MCT over a much broader range of the von Schweidler exponent values than has been studied for simple atomic liquids. We also show how structural changes are reflected in the wave-vector dependence of dynamic properties of the liquid along a path of nearly constant diffusivity. For temperatures below the crossover temperature of MCT (where the predictions of MCT are expected to fail), we find tentative evidence for a crossover of the temperature dependence of the diffusivity from power-law to Arrhenius behavior, with an activation energy typical of a strong liquid.